Magnetoencephalography (MEG) systems are advanced neuroimaging tools used to measure the magnetic fields produced by neuronal activity in the human brain. However, they require significant amounts of liquid helium to keep the superconducting quantum interference device (SQUID) sensors in a stable superconducting state. Additionally, MEG systems must be installed in a magnetically shielded room to minimize interference from external magnetic fields. We have developed an advanced MEG system that incorporates a superconducting magnetic shield and a zero-boil-off system. This system overcomes the typical limitations of traditional MEG systems, such as the frequent need for liquid helium refills and the spatial constraints imposed by magnetically shielded rooms. To validate the system, we conducted an evaluation using signal source estimation. This involved a phantom with 50 current sources of known location and magnitude under active zero-boil-off conditions. Our evaluations focused on the precision of the magnetic field distribution and the quantification of estimation errors. We achieved a consistent magnetic field distribution that matched the source current, maintaining an estimation error margin within 3.5 mm, regardless of the frequency of the signal source current. These findings affirm the practicality and efficacy of the system.

Background/Objectives: The dichotic listening test (DLT) is widely used to assess auditory attention and hemispheric language lateralization, with the right-ear advantage (REA) representing a robust behavioral phenomenon. Although the REA is often attributed to structural asymmetries in auditory pathways and left-hemisphere dominance for speech processing, the neural mechanisms by which selective attention modulates this asymmetry remain unclear. This study examined how directed auditory attention influences the REA and its neural correlates using magnetoencephalography (MEG)-based auditory steady-state responses (ASSRs). Methods: Fifteen right-handed participants performed directed-attention dichotic listening tasks during MEG recording. One participant was excluded from MEG analyses due to excessive noise contamination, resulting in 14 participants included in neural analyses. Participants attended to either the left or right ear throughout each session and reported the perceived stimulus from the attended ear. Dichotic speech stimuli were amplitude-modulated at 35 Hz and 45 Hz for frequency tagging. ASSR amplitudes were extracted from the left and right auditory cortices and analyzed in relation to behavioral accuracy using correlation analyses and analysis of covariance (ANCOVA). Results: Behavioral accuracy was significantly higher during right-ear attention than left-ear attention, indicating a residual REA. ASSR amplitudes tended to be higher during left-ear attention. Importantly, during left-ear attention, ASSR amplitude in the left auditory cortex showed a significant positive correlation with behavioral accuracy, whereas no such association was observed during right-ear attention. Conclusions: These findings indicate that the REA reflects a dynamic interaction between structural auditory asymmetry and top-down attentional control, with successful left-ear listening relying on compensatory recruitment of the left auditory cortex.